How do you fill 20 hours with someone who is constantly talking about non-relevant topics, but is very sweet?
Oh dear, my dad was the sweetest man ever. Kind, caring, considerate, funny, witty and very good company but I was with him 24/7 and it was very wearing. I feel mean for saying that but there are only so many times that you can have the same conversations without it driving you mad. I have no answers but sometimes I let it float over my head and at other times I would distract with a 'would you like a coffee dad' or I would just disappear back to my jigsaw puzzle and hope for a bit of peace.
Don't feel guilty for feeling like this, dementia can try the patience of a saint, I know this, I have been there and the frustration is very real. You are doing the best you can in a difficult situation and you can do no more. Just try to find an escape somewhere. I know this is not helpful but it is the best I can think of at the moment. sorry I am not more helpful but I remember it well.